In 1872 Charles Darwin issued The Expression of the Emotions in Man and Animals through his publisher, John Murray. This book, which contained numerous wood-engraved text illustrations, was also illustrated with seven heliotype plates of photographs by pioneering art photogapher Oscar Gustave Rejlander, and was the only book by Darwin illustrated with photographs.
“With this book Darwin founded the study of ethology (animal behavior) and conveyance of information (communication theory) and made a major contribution to psychology” (DSB). Written as a rebuttal to the idea that the facial muscles of expression in humans were a special endowment, the work contained studies of facial and other types of expression (sounds, erection of hair, etc.) in man and mammals, and their correlation with various emotions such as grief, love, anger, fear and shame. The results of Darwin’s investigations showed that in many cases expression is not learned but innate, and enabled Darwin to formulate three principles governing the expression of emotions—relief of sensation or desire, antithesis, and reflex action.